Vitamin D2026-07

Association between vitamin D deficiency and type 2 diabetes in an Indigenous Brazilian population.

Santos Hully Cantão Dos, Alvim Rafael de Oliveira, Quinte Gabriela Callo, Faria Carolina Perim de et al. — Archives of endocrinology and metabolism

Summary

A study among Indigenous adults in Brazil found a connection between lower vitamin D levels and a higher likelihood of having type 2 diabetes. This suggests that maintaining adequate vitamin D might be an important factor in managing diabetes risk, even in populations with significant sun exposure.

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Key points

Lower vitamin D levels were associated with a higher chance of having type 2 diabetes.
This link was observed in Indigenous Brazilian adults from specific ethnic groups.
Individuals with vitamin D deficiency had nearly double the odds of having type 2 diabetes.
The findings highlight a potential public health concern regarding vitamin D status in this population.

What the study looked at

### What question the study asked Researchers wanted to investigate if there was a relationship between vitamin D levels and the presence of type 2 diabetes among Indigenous adults living on a reserve in southeastern Brazil. ### How it was studied (design/participants) This was a cross-sectional study conducted between 2020 and 2022, involving 946 Indigenous adults (aged 20 years or older) from the Tupiniquim and Guarani ethnic groups. The study measured participants' vitamin D levels and assessed whether they had type 2 diabetes based on self-reports, medication use, or blood glucose tests. Statistical methods were then used to determine if there was an association between vitamin D status and diabetes, while accounting for other influencing factors. ### What it found The study found a clear association: individuals with lower vitamin D levels were more likely to have type 2 diabetes. Specifically, those categorized as vitamin D deficient had nearly twice the odds of having type 2 diabetes compared to those with adequate vitamin D levels. This link remained significant even after considering other factors that could affect diabetes risk.

Dietary takeaway

While this study doesn't prove that low vitamin D causes type 2 diabetes, it adds to the evidence suggesting a potential link. To support healthy vitamin D levels, consider incorporating vitamin D-rich foods like fatty fish (salmon, mackerel) and fortified dairy or plant-based milks into your diet. Sunlight exposure is also a natural source, but always remember that one study alone cannot provide definitive health advice, and individual needs may vary.

Abstract

OBJECTIVE: This study investigated the association between vitamin D levels and type 2 diabetes mellitus (T2DM) among Indigenous adults of the Tupiniquim and Guarani ethnicities residing on a reserve on the southeastern Brazilian coast. SUBJECTS AND METHODS: This cross-sectional study, conducted between 2020 and 2022, included 946 Indigenous individuals (aged ≥20 years, both sexes) from the Tupiniquim and Guarani ethnic groups. T2DM was defined by a self-reported diabetes diagnosis, the use of glucose-lowering medications, or, in the absence of such reports, a fasting plasma glucose level ≥126 mg/dL, a 2-hour plasma glucose level ≥200 mg/dL following an oral glucose tolerance test, or a glycated hemoglobin level ≥6.5%. Hypovitaminosis D was defined as a serum 25-hydroxyvitamin D [25(OH)D] level <30.0 ng/mL. Associations were estimated using multiple logistic regression models. RESULTS: The mean age of the participants was 41.3 ± 14.9 years; 56.8% were women, and 90% belonged to the Tupiniquim ethnic group. After adjusting for confounders, serum 25(OH)D levels were inversely associated with T2DM. Each 1-ng/mL increase in 25(OH)D was associated with lower odds of T2DM (OR = 0.96; 95% CI: 0.94-0.98). Individuals with hypovitaminosis D had higher odds of T2DM than those with adequate vitamin D levels (OR = 1.77; 95% CI: 1.20-2.62). CONCLUSION: Vitamin D deficiency was independently associated with the presence of T2DM. The high prevalence of hypovitaminosis D underscores the importance of screening strategies and considering supplementation protocols, even among Indigenous populations with high solar exposure.

View on PubMed →DOI: 10.20945/2359-4292-2026-0084